Birds Flashcards
What are some general characteristics of birds?
4 chambered heart. Toothless beak. Hollow-boned. Egg laying. Flight capable.
From what group of dinosaurs are birds meant to be descended from?
Dromaeosaurs.
What bird-like features were possessed by dromaeosaurs like Compsognathus?
Long spindly legs + long neck.
Small head + large eyes.
Pubic bone rotation + fused clavicles.
Outwards arm rotation.
What dinosaur features remained in dromaeosaurs like Compsognathus?
Clawed hands.
Teeth.
Long bulky tail.
What were some species within the “proto-bird” assemblage?
Sinornithosaurus.
Caudipteryx.
Protarchaeopteryx.
What bird-like features were possessed by Archaeopteryx?
Long spindly legs + long neck. Small head + large eyes. Pubic bone rotated backwards + fused clavicles. Bird like feet. "Modern" flight + contour feathers.
What dinosaur features were possessed by Archaeopteryx?
3 clawed hands. Long (but thin) bony tail. Teeth. Small sternum. Solid bones.
What bird-like features were possessed by Confuciusornis and Enantiornithes?
Hollow bones and a pygostyle (a bone used to control the tail feathers).
What vestigial dinosaur-like feature is possessed by hoatzin chicks?
2 vestigial wing claws.
What is the clade Euornithes?
The “early true birds”. Includes Patagopteryx, Ichthyornis and Hesperornis.
How many modern bird lineages are there and what are their names?
Palaeognathae, Neoaves and Galloanserae.
What orders are included in the group Palaeognathae?
Tinamous, Rheas, Ostriches, Kiwis, Cassowaries and Emus.
What are some features of the group Palaeognathae?
Large (excluding tinamous) and flightless (excluding tinamous).
How many orders are there in the lineage Neoaves?
35 orders (83 families).
Which is the most speciose order within Neoaves?
The Passerines with over 5000 named species. There are 3 suborders: Acanthisitti, Tyranni and Passeri.
How many orders are there in the lineage Galloanserae?
2 orders (8 families).
What are the names of the orders in the lineage Galloanserae?
Anseriformes and Galliformes.
How many orders are there in the lineage Palaeognathae?
6 orders (6 families).
What birds are found in the order Anseriformes?
Most water birds such as ducks, geese and swans.
What birds are found in the order Galliformes?
Grouse, pheasants, New World quails and guinea fowls.
How many species of bird are there globally?
9-10,000 making them the most speciose tetrapod group.
How many bird species have been lost during the Anthropocene extinctions?
Around 2000 species.
What are some feather types?
Pennaceous/Vaned. Filoplume. Bristle. Flight. Semiplume. Down.
Describe the structure of a feather.
A vane made up of barbs which is attached to the shaft. The barbs possess barbules with hooks (barbicels)
What are the upper and lower half of the shaft known as?
Upper half = rachis.
Lower half = calamus.
What is the preen gland and where is it located?
A gland that secretes preen oil found at the base of the tail.
Which species possess a preen gland?
Waterbirds.
What is powder down?
A powdery substance produced by some birds that cleans and waterproofs the feathers. It can also prevent parasites.
What is the process of anting?
The bird sits on an ant nest so the ants climb onto it. The ants then remove any external parasites.
Why is moulting necessary?
To replace damaged or worn feathers.
Which colours are reflected by caratenoid pigments?
Yellow and red.
Which colours are reflected by pterin pigments?
White, yellow and red.
Which colours are reflected by quinone pigments?
Yellow, red and orange.
Which colours are reflected by verdin pigments?
Blue and green.
What colours are reflected by porphyrins?
Depends on the metal ion: iron = red, magnesium = green and copper = red/violet/green.
What colours are reflected by melanin?
Dark brown and black.
What can pigmentation be used to indicate?
Foraging proficiency, age, rank or testosterone levels.
What are the 2 forms of structural colours?
Scattering and multilayer interference.
What strategies do birds use for body temperature regulation?
Complete homiothermy.
Strategic hypothermia.
Torpor.
Hibernation.
What distinguishes primary feathers?
Outermost feathers.
Larger in size.
Propel bird through air.
Attached to “hand” bones.
What distinguishes secondary feathers?
Innermost feathers.
Smaller in size.
Provide lift.
Run along the “forearm” bones.
What are the benefits of flight?
Escape opportunities. Catching prey. Access to nest sites. Larger home range. Display flights.
What is the trees-down model for flight evolution?
Similar to “flying” squirrels/lizards etc. Foot morphology goes against this theory - not capable of climbing.
What is the wing-assisted pouncing model for flight evolution?
Swooping down to catch prey from a vantage point. Supported by Archaeopteryx evidence - poorly adapted for flapping but advanced feathers.
What is the ground-up model for flight evolution?
Similar to swan take-off. Unlikely early birds could run fast enough (12kph+).
What is the wing-assisted incline-running model for flight evolution?
Upstrokes give feet increased grip but Archaeopteryx had a very weak upstroke.
What is the wing-assisted water-walking model for flight evolution?
Similar to basilisk lizards crossing water.
How do wings work?
Air has to travel further over the upper wing surface so has to move at a faster velocity. This results in lower pressure creating lift.
How are the wings utilised by birds?
During flapping the downstroke increases pressure on the lower wing surface increasing lift.
Why do modern birds typically possess toothless, non-keratinised bills?
Loss of teeth and keratinisation makes the head lighter which contributes to more efficient flight.
In what group have tooth-like structures re-evolved? Why has this occurred?
Saw-bills, a group of ducks including goosanders. Keratin ridges have replaced enamilised teeth and are used to handle slippery fish.
Define character displacement.
Anatomical changes in response to the selective environment that the organism faces at the time.
How does the syrinx produce sound?
By vibrating one or both walls of the internal airway structure.
What are the walls of the internal airways known as? What is their function during singing?
The 2 medial tympaniform membranes. They can vibrate at different frequencies to give 2 “voices”.
What is the function of a bill casque?
To act as a resonating chamber to modify their calls.
